Brontosaurus is one of the most famous dinosaurs to ever exist, except for years it didn't exist. Briefly, the history goes like this: in 1877 O.C. Marsh named a juvenile specimen Apatosaurus ("Deceptive Lizard"). Two years later he discovered a similar adult specimen which he described as a unique genus and species, and named is Brontosaurus ("Thunder Lizard"). Though in 1903 Elmer Riggs wrote that the two were not different enough to warrant the distinction and therefore that the second specimen must also be an Apatosaurus, the name Brontosaurus stuck and has been lodged in our hearts ever since.
Today our intractable affection for the "mythical" Brontosaurus may have been validated. A team of researchers have been studying a number of skeletons as part of a larger project to reassess Diplodocidae, the family that includes Apatosaurus, and many are convinced that there is enough evidence to bring Brontosaurus back. From The Guardian:
The scientists analysed 81 skeletons and measured around 477 anatomical traits to create a new evolutionary family tree. Statistically, two main groups emerged: one containing more slender species, such as Diplodocus, and a second containing the bulkier Apatosaurus. Within the Apatosaurus group, though, further considerable distinctions were found. Apatosaurus had a thicker neck than the original Brontosaurus specimens, and differences were seen in the shape of their shoulder blades and ankle bones, according to the PeerJ report.
“The differences we found between Brontosaurus and Apatosaurus were at least as numerous as the ones between other closely related genera, and much more than what you normally find between species,” said Roger Benson, a co-author from the University of Oxford.
Friend of TDN Brian Switek is quoted in the same article:
“I want to believe, but I’m not sure the Brontosaurus is here to stay just yet,” said Switek.The problem, he says, is that there is no standard way of picking which anatomical traits are significant, meaning there is a degree of subjectivity in drawing lines between related genera. Using a different set of anatomical markers could easily sink Brontosaurus back into the Apatosaurus genus. The question is unlikely to be definitively agreed, Switek predicts, without the discovery of fresh fossils, in particular a Brontosaurus skull, which has never been found.
You can read Switek's take on this news at Smithsonian.com, and more about the story at ScienceDaily.com, ScientificAmerican.com, and pretty much anywhere dinosaur enthusiasts gather on the internet.
